This invention relates to a support bracket for an electrical insulator and more particularly to an insulator support bracket adapted to carry an insulator element for supporting an electrical conductor member in spaced relation to a supporting structure, such as a pole for supporting a conductor of an electrical transmission line.
As is well known in the art to which my invention relates, the major complaint by electrical utilities against the use of fiberglass support brackets for insulator elements is that erosion occurs along the surface of prior art type fiberglass support brackets, thus resulting in a short life and reduction of the mechanical and electrical characteristics of such fiberglass support brackets. This erosion is primarily caused by leakage current flowing from the insulator element across the fiberglass support bracket to ground. This deterioration is proportional to the amount of current flow. That is, the higher the current, the more rapid the deterioration since the resistance to the current flow produces heat which breaks down or carbonizes the surface of the fiberglass support bracket. Accordingly, still greater amounts of current are permitted to flow across the surface of the support bracket whereby an ever-worsening condition is created until the insulator support bracket is weakened to the point that it fails under its mechanical load and/or loses its electrical insulating characteristics.
Another factor which greatly increases the leakage of current across the insulator is that in recent years a semiconductive coating has been applied to the top and around the neck of porcelain insulators. This additional increase in leakage of current further exaggerates the deterioration of the insulator support bracket.
As is well known, the reason for employing insulating support brackets is to remove the phase conductors off and away from the pole or other supporting structure to meet the National Electric Code requirements for safety reasons. It is thus recognized that such support brackets must be sufficiently strong to support the load imparted thereto by the weight of the conductors and at the same time must be adapted to separate the conductors to prevent them from coming together or moving into close proximity to each other and thus create a short circuit.